An m-unit cage is used to hold together m drives such as optical disk drives (ODDs), floppy disk drives (FDDs), hard disk drives (HDDs), and other drives. Separate securing plates and a plurality of screws are used to fasten the drives to the m-unit cage. For example, FIGS. 1A-1B illustrate a three-unit cage 100 for holding together two ODDs 105 and one FDD 110. The two ODDs 105 are positioned above the FDD 110. The three-unit cage 100 is built using an ODD securing plate 115 and a FDD securing plate 120, as illustrated in FIGS. 1C-1D, respectively. Both the ODD securing plate 115 and the FDD securing plate 120 are typically formed in a single stamping operation on sheet metal and are separate from the three-unit cage 100. As illustrated in FIG. 1C, the ODD securing plate 115 comprises a ledge 125 along a top, a pair of supports 130 located at bottom opposite ends, and two pairs of contact springs 140. A first pair of contact springs 140 is located on a top surface of the ODD securing plate 115 near the ledge 125. A second pair of contact springs 140 is located at the bottom of the ODD securing plate 115. Both pairs of contact springs 140 depress against ODD screws that are attached to the ODD. As illustrated in FIG. 1D, the FDD securing plate 120 comprises a bar 145 and a pair of contact springs 140′ located at a bottom of the bar 145. The pair of contact springs 140′ depresses against FDD screws that are attached to the FDD. The ODD securing plate 115 and the FDD securing plate 120 may have additional holes to attach the plates 115, 120 to the three-unit cage 100 and/or other accessories by using additional screws.
FIG. 2A illustrates a one-unit cage 200 for holding a HDD 205. The one-unit cage 200 is built using a HDD securing plate 210, as illustrated in FIG. 2B. The HDD securing plate 210 is typically formed in a single stamping operation on sheet metal and is separate from the one-unit cage 200. As illustrated in FIG. 2B, the HDD securing plate 210 comprises a bar 215, two ledges 220 located at a top opposite ends of the bar 215, and a pair of contact springs 225 located at a bottom of the bar 215. The pair of contact springs 225 depresses against HDD screws that are attached to the HDD. The HDD securing plate 210 may have additional holes to attach the plate 210 to the one-unit cage 200 and/or other accessories by using additional screws.
Prior art cages and securing plates suffer from a number of shortcomings. For example, contact springs of the securing plates do not provide enough clamping force or friction to prevent drives within a cage from vibrating. As such, when the drives vibrate within the cage, the cage rattles, creating disturbing and often loud noises. Typically, the clamping force exerted by one contact spring against a device is 0.85 kgf. In addition, since the securing plates are separate components from the cage, use of the securing plates is an extra cost. Furthermore, the securing plates can be lost or misplaced.
The present invention addresses at least these limitations in the prior art.